i.e. he did not accept the division of the ovum into blasto- 

 meres, but their endogenous formation in the ovum. Bergman 

 raised an objection to Shvani and compared the blastomeres 

 formation to the division of plant cells. Reichert, on the 

 contrary, confirmed that he could observe in the frog's egg, 

 up to splitting, sphere-like accumulations of granules of 

 nutritive substances, which were equated by him to cells. 

 Kolliker suggested that, turned into the cells of the 

 embryonic tissues were not the spheres of splitting themselves, 

 but vesicles, noticed in the eggs of frogs which, later on, 

 were identified as cellular nuclei. At the same time, the 

 surrounding yolk substances of spheres of splitting are dis- 

 solved. In fact, Kolliker shortly afterwards retracted these 

 opinions. 



The Baer presentation that each step of splitting is 

 forewarded by a nucleus division was confirmed in the investiga- 

 tions of N. A. Warnek (1850) on the eggs of gastropod molluscs 

 (see chapter 25) and I. Miiller, who studied the development of 

 ova of Entoooncha mivabitis , a mollusc which parasitizes on 

 sea cucumbers. Warnek and Miiller's works on eggs of molluscs 

 and Remak's work on frogs' eggs showed, that the embryonic 

 vesicle of the egg was divided into light spots (nuclei) of 

 cells of splitting (426) . 



(109) Martin Henrich Rathke (1793-1860) after finishing 

 the Gettingensky University, where he studied natural sciences 

 and medicine, worked as school teacher and practical physician 

 in Dantsig for over 16 years. During this time, Rathke gained 

 fame due to many valuable works in the field of comparative 

 anatomy and embryology. In view of this he was invited to 

 Derptsky University, where he lectured on physiology and general 

 pathology as well as zoology and comparative anatomy (1829-1835) 

 S. S. Kutorgaya was among his students, later on he worked as 

 professor at Petersburg University. Rathke is the author of a 

 great number (more than 125) of works, mainly of embryological 

 contents. His name is connected with the discovery of embryonic 

 plates in crayfish and branchiate slits in the mammalian embryos 

 as well as provisory kidneys in all vertebrates. At first, the 

 primary bundle was described by K. F. Wolff in chicken embryo, 

 therefore, Rathke suggested for this organ the name Wolff's 

 body, which is maintained in recent embryology. 



643 



